1. Field of the Invention
The present invention relates to a leadless type semiconductor package having no outer leads outwardly extending from a periphery thereof, and a production process for manufacturing such a leadless type semiconductor package.
2. Description of the Related Art
Conventionally, a semiconductor package includes an island or plate-like mount, a semiconductor chip mounted on the plate-like mount, a plurality of leads electrically connected to the semiconductor chip, and a molded resin enveloper sealing and encapsulating the plate-like mount, the semiconductor chip, and the inner portions of the leads. Thus, the outer portions of the leads outwardly and laterally extend from sides of the molded resin enveloper, and the conventional semiconductor package is mounted on a wiring board such that the outer portions of the leads are electrically contacted with and bonded to electrode pads formed on the wiring board. Of course, this conventional semiconductor package is undesirable in application to a miniature or compact piece of electronic equipment in that the outwardly and laterally extending outer portions of the leads result in overall bulkiness of the semiconductor package.
JP-A-(HEI)11-150143 (Japanese Letters Patent No. 3074264) discloses a leadless type semiconductor package more compactly arranged in comparison with the aforesaid conventional semiconductor package. In particular, the leadless type semiconductor package includes an island or plate-like mount, a semiconductor chip mounted on the plate-like mount having electrode pads provided on a top surface thereof, a molded resin enveloper sealing and encapsulating the semiconductor chip, and metal electrode pads provided on a rear surface of the molded resin enveloper and electrically connected to the electrode pads of the semiconductor chip through the intermediary of bonding wires.
The leadless type semiconductor package is mounted on a wiring board such that the metal electrode pads of the molded resin enveloper are electrically contacted with and bonded to electrode pads formed on the wiring board.
The leadless type semiconductor package is more compact in comparison with the first-mentioned conventional semiconductor package because this semiconductor package has no outer lead portions extending outwardly and laterally from sides of the molded resin enveloper. Nevertheless, the leadless type semiconductor package necessarily has a relatively large thickness in that the bonding wires are used to establish the electrical connection between the electrode pads of the semiconductor chip and the metal electrode pads of the resin molded enveloper. Namely, it is necessary to provide a relatively high space for the laying of the bonding wires, resulting in the large thickness of the leadless type semiconductor package itself.